Hi Paul,
Thanks for your comment, I have not yet compared an SG800 to the SCP600 in terms of colour gamut. I would be surprised if the SG800 had a similar range, but I would stand to be corrected if I found that to be untrue. I am on the hunt for a good second hand one to do some comparison test though :)
The Inktec inks do have use by dates these are printed on the label of the ink bottle. A general rule of thumb for me is the inks will have 2 years shelf life / until the use by date expires when they arrive with me. I usually turn stock around within 3 months so the end user gets at least 18 months from date of purchase.
As with Sawgrass and any other sublimation ink, going past the use by date is a risk and can lead to issues with the ink and in turn the printer you're using out of dates in. Usual issues are ghosted or blurred nozzles (so they are not straight and true) this is because the dye particulars have started to break down in the ink.
Regular inks like those used in your 3880 may not have issues as they are pigment based. But sublimation inks do appear to get issues when they expire.
All our Inktec inks can be purchased in individual ink bottles (100ml up to 1 litre) so you can buy whatever colour you need and replace when you need keeping everything in good order and expiration date.
Alex